Share-Based Compensation - Allocated Share-based Compensation Costs (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Employee Service Share Based Compensation Allocation Of Recognized Period Costs [Line Items]
Share-based compensation costs	$ 10.1	$ 14.1	$ 18.8
Cost of Revenue
Employee Service Share Based Compensation Allocation Of Recognized Period Costs [Line Items]
Share-based compensation costs	2.5	2.7	2.2
Selling, General and Administrative Expenses
Employee Service Share Based Compensation Allocation Of Recognized Period Costs [Line Items]
Share-based compensation costs	7.6	6.2	3.4
Restructuring and Related Charges
Employee Service Share Based Compensation Allocation Of Recognized Period Costs [Line Items]
Share-based compensation costs		0.8
Continuing Operations
Employee Service Share Based Compensation Allocation Of Recognized Period Costs [Line Items]
Share-based compensation costs	10.1	9.7	5.6
Total income tax benefit recognized in continuing operations	$ 2.6	2.5	1.4
Discontinued Operations
Employee Service Share Based Compensation Allocation Of Recognized Period Costs [Line Items]
Share-based compensation costs		$ 4.4	$ 13.2